Porous microneedles on a paper for screening test of prediabetes

Porous microneedles are expected to have a variety of potential for applications in diagnostics owing to their ability to penetrate human skin painlessly and extract bio-fluid by capillary action. In this paper, a ‘Porous Microneedle on a Paper substrate’ (PMP) is proposed as a novel platform for direct integration of sensors. A microneedle array with height of approximately 840 μm was prepared on a paper. The fabrication process consists of salt leaching and heat press moulding. In this method, the salt particles are utilized as porogen materials. Mixture of the biodegradable polymer and the salt was shaped into microneedles by moulding. Furthermore, the polymer penetrated the paper matrix owing to heating during the pressing process. Subsequently, the salt particles are removed to develop the porous structure. Various ratios of salt to polymer were investigated to adjust the porosity of microneedles as well as their sample absorption property. A paper-based glucose sensor was integrated into the platform to demonstrate the absorption property of the microneedles, and showed successful sample extraction and glucose concentration analysis from agarose gel-based skin mimic. The developed platform has the potential to integrate various paper-based bio-sensors to painless, disposal and fast screening and diagnostic test for patient, as well as those with prediabetes.